Pneumatic tire and vehicle with pneumatic tire

Abstract

A side-reinforced run-flat tire with improved run-flat durability and riding comfort is easily compression-molded using a conventional bladder. The tire includes a tread ( 2 ), shoulder portions ( 3 ), side walls ( 4 ), and beads ( 5 ), each including a bead core ( 6 ) and a bead filler ( 7 ). A carcass ply ( 8 ) having a main part ( 8 a ) and a folded part ( 8 b ) extending from a crown ( 9 ) along the inner sides of the shoulder portions ( 3 ) and the side walls ( 4 ) to the beads ( 5 ), and folded around the outer surfaces of bead cores ( 6 ) from the inner sides to the outer sides of the bead cores in the tire width direction so as to run up in the tire radial direction outwardly. Reinforcement rubber layers ( 11 ) are widthwise provided on the inner sides of the side walls ( 4 ). A bead-reinforcing layer ( 12 ) is provided on a side (left in drawing) undergoing larger stress during run-flat driving. The rubber layers, which are symmetric with respect to the equator, enable the tire to be easily compression-molded using a conventional bladder.

1 . A pneumatic tire comprising:
 a tread;   a pair of side walls extending from the right and left sides, respectively, of the tread inward in the tire radial direction;   a pair of beads extending from the respective side walls, each bead having a bead core and a bead filler;   a carcass ply extending from the tread along the side walls to the beads, and being folded around the outer surfaces of the bead cores from the inner sides to the outer sides of the bead cores in the tire width direction so as to run up in the tire radial direction outwardly; and   a pair of right and left reinforcement rubber layers respectively provided in the inner sides of the side walls in the tire width direction,   one of the pair of the beads being a reinforced bead that suppresses deflection of the side wall during run-flat driving.   
   
   
       2 . The pneumatic tire according to  claim 1 , wherein
 the reinforced bead is reinforced with a bead-reinforcing layer provided in the tire radial direction in the bead.   
   
   
       3 . The pneumatic tire according to  claim 2 , wherein
 the bead-reinforcing layer has an upper end in the tire radial direction at a position that is at about 30% or more of the tire height and at 80% or less of the height of the carcass ply having a maximum width.   
   
   
       4 . The pneumatic tire according to  claim 2 , wherein
 the bead-reinforcing layer has a lower end in the tire radial direction at a position above the upper end of the bead core and at about 15% or less of the tire height.   
   
   
       5 . The pneumatic tire according to  claim 2 , wherein
 the bead-reinforcing layer is arranged on the outside of the folded part of the carcass ply, between the folded part of the carcass ply and the bead filler, or between the bead filler and the extension of the carcass ply.   
   
   
       6 . The pneumatic tire according to  claim 2 , wherein
 the bead-reinforcing layer is a ply that includes steel cord or steel wire therein.   
   
   
       7 . The pneumatic tire according to  claim 1 , wherein
 the reinforced bead is reinforced by a first bead filler that has an elastic modulus higher than the elastic modulus of a second bead filler of the other bead.   
   
   
       8 . The pneumatic tire according to  claim 7 , wherein
 the elastic modulus of the first bead filler is 125 to 150% that of the second bead filler.   
   
   
       9 . The pneumatic tire according to  claim 7 , wherein
 the first bead filler has an upper end in the tire radial direction at a position that is at about 50% or less of the tire height.   
   
   
       10 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 1  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       11 . The vehicle equipped with a pneumatic tire according to  claim 10 , wherein
 the tire is mounted to a wheel having a zero or positive camber angle such that the reinforced bead resides on the outer side of the vehicle.   
   
   
       12 . The vehicle equipped with a pneumatic tire according to  claim 10 , wherein
 the tire is mounted to a wheel having a negative camber angle such that the reinforced bead resides on the inner side of the vehicle.   
   
   
       13 . The vehicle equipped with a pneumatic tire according to  claim 10 , wherein
 the tire is mounted to a front wheel such that the reinforced bead resides on the outer side of the vehicle, or mounted to a rear wheel such that the reinforced bead resides on the inner side of the vehicle.   
   
   
       14 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 2  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       15 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 3  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       16 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 4  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       17 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 5  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       18 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 6  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       19 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 7  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.   
   
   
       20 . A vehicle equipped with a pneumatic tire, comprising:
 the pneumatic tire according to  claim 8  that is mounted to the vehicle so that the reinforced bead resides at a position undergoing relatively large stress during run-flat driving.